Invertebrates Part III

Joint-legged Animals

The animals in this section of the Salt Corner Animal Library are properly called 'joint-legged animals.' They are in the Phylum Arthropoda, which is one of 36 phyla in the Kingdom Animalia (there are five kingdoms containing flora and fauna). In fact, representatives in 28 of the 36 are found in marine environments with some not visible to the human eye. Nevertheless, for marine hobbyist purposes, those of interest, e.g., shrimp, crabs, lobsters, etc., will be discussed here.

As for the 'arrangement' of various classes/orders/families/genera, etc., they are just that, as I've found associated Taxon information coming from various websites not only confusing for a non-scientist such as myself, but actually quite different depending upon the source, although, Wikipedia was mostly used here. Apparently, there's still much indecision as to what goes where, and the following should be considered a work in progress.

Kingdom: Animalia

Phylum: Arthropoda
(joint-legged animals)

Subphylum: Chelicerata

Class: Arachnida (mostly land-dwelling spiders, scorpions, ticks, mites)

Class: Pycnogonida (sea spiders)


Class: Merostomata
Order: Xiphosura (horseshoe crabs, king crabs)


Subphylum: Crustacea
Class: Branchiopoda (mostly freshwater/water fleas)
Subclass: Phyllopoda
Superorder: Diplostraca
Order: Cladocera (water fleas)
Infraorder: Anomopoda
Infraorder: Ctenopoda
Suborder: Eucladocera
Infraorder: Haplopoda
Suborder: Cyclestherida
Suborder: Laevicaudata
Suborder: Spinicaudata
Order: Notostraca (fairy shrimp & phyllopods)
Subclass: Sarsostraca
Order: Anostraca (freshwater/brine shrimp/Artemia)


Class: Malacostraca (crabs, lobsters, prawns, shrimp, amphipods, isopods, crayfish)

Subclass: Phyllocarida (mostly extinct)
Order: Leptostraca
Order: Archaeostraca
Order: Hoplostraca

Subclass: Hoplocarida
Order: Stomatopoda (mantis shrimp)

Subclass: Eumalacostraca
Superorder: Eucarida
Order: Amphionidacea
Order: Decapoda (shrimp, prawns, lobsters, hermit crabs, true crabs)

Order: Euphausiacea (krill)
Superorder: Peracarida
Order: Amphipoda (sandhoppers)
Order: Cumacea (cumaceans)
Order: Isopoda
Order: Lophogastrida (opossum shrimp)
Order: Mictacea
Order: Mysidacea (mysids shrimp)
Order: Tanaidacea (minor crustaceans)
Order: Spelaeogriphacea
Order: Thermosbaenacea
Superorder: Syncarida
Order: Anaspidacea
Order: Bathynellacea
Order: Palaeocaridacea


Class: Maxillopoda
(barnacles and parasites/copepods)
Subclass: Thecostraca
Infraclass: Cirripedia (curl-footed)
Superorder: Thoracica
Order: Pedunculata
Suborder: Lepadomorpha
Order: Sessilia
Superfamily Tetraclitoidea
Subclass: Copepoda
Order: Calanoida
Suborder: Lepadomorpha
Family Lepadidae


Class: Remipeda (cave dwelling blind shrimp)
Order: Enantiopoda (Extinct)
Order: Nectiopoda


Class: Ostracoda (seed shrimp)
Subclass: Podocopa
Order: Podocopidae


Class: Cephalocarida (small primitive shrimp)
Order: Brachypoda (horseshoe shrimps)

In the Subphylum Chelicerata, there are three classes, yet only two have creatures of interest; its Class Pycnogonida containing 'sea spiders' will be discussed in an add-on section to this library in the future, and the Class Merostomata containing the horseshoe crab, which is discussed at the end of this section. The main areas of interest are in the Subphylum Crustacea, and those are more fully discussed elsewhere in this section.

As noted in the other sections of my Animal Library, there's room for additions, and no doubt corrections. I've laid the groundwork, so please let's not criticize, simply pitch in and help! Together we can make this 'Animal Library' for hobbyists and divers the best in the world. I should also add that since the supply of invertebrate photos from individuals appears to be somewhat scarce in certain categories, I've searched the web to find sites where none-copyrighted examples appeared to be available and/or sought permission to use their photos. I've posted these here with the website where located, such as the wonderful site at National Oceanic & Atmospheric Administration (NOAA) and www.edge-of-reef.com. By visiting the sites mentioned you might be able to gather more information about the species of interest. And if you have better photos, and/or more species information, please send it to me, as sharing is what this non-profit site is all about! (Email to saltcorner@cs.com.) Where photos were not available, I've noted books where you can find a photo of the discussed species.

Please be advised that when time allows, I like to update various sections of my Animal Library. Because of the way it's constructed, some new orders/families/genera additions cannot go into the old format without redoing the 'entire' library. Therefore, they will be placed into an additional section named after the section was updated, e.g., for this section, new additions will appear in the "Oddballs" folder at the end of the invertebrate library. Look for those there, as sea spiders will be one of the additions.

In closing, there are many different 'joint-legged' creatures of interest, at least in some cases, so lets begin looking at some of the little bug-like crustaceans, such as such copepods, isopods, and amphipods, and also the mysids/mysis shrimp and krill that are used as foodstuffs. Then move to a couple of barnacles, then on to the Order Decapoda, which actually contains the ornamental shrimps, lobsters, crabs (hermits) squat lobsters, and true crabs of major interest. Then finish up with horseshoe crabs, which belong in a totally different Phylum, as they have nothing to do with crabs, as they are more closely related to scorpions and spiders.

Barnacles
Copepods - Mysids - 'Krill' - Isopods - Amphipods
Shrimp
Lobsters
Hermit Crabs
True Crabs and Porcelain Crabs
Oddballs


Soft Corals - Hydrocorals - Octocorals 1 - Octocorals 2 - Octocorals 3 - Octocorals4 - Gorgonia/Sea Pens - Sea Anemones - Corallimorpharia - Zoanthids - Black Corals - Oddballs
Stony Corals - Acanthastrea - Acropora - Alveopora - Blastomussa - Caryophyllia - Catalaphyllia - Caulastrea - Cynarina - Diploria - Euphyllia - Favia - Favites - Fungia - Galaxea - Goniopora - Heliofungia - Herpolitha - Hydnophora - Leptoria - Lobophyllia - Montastraea - Montipora - Mussa - Mycedium - Nemenzophyllia - Oculina - Pachyseris - Pavona - Physogyra - Platygyra - Plerogyra - Pocillopora - Porites - Scolymia - Seriatopora - Stylophora - Symphyllia - Trachyphyllia - Tubastraea - Turbinaria - Oddballs
Joint-Legged Animals - Copepods, Mysis, Krill, Isopods, and Amphipods - Barnacles - Shrimp - Lobsters - Hermit Crabs - True Crabs - Oddballs
Molluscs - Clams - Snails/Abalone/Limpets - Sea Hares/Slugs/Nudibranchs - Octopi/Cuttlefish/Squid/Nautilus - Oddballs
Echinoderms - Sea Lilies/Feather Stars - Starfish/Sea Stars and Basket Stars - Brittle Stars - Urchins/Heart Urchins/Sand Dollars - Sea Cucumbers - Oddballs
Other Inverts - Sponges - Jellyfish - Sea Squirts - Worms - Plankton - Oddballs

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